Siderochromes are microbial iron chelates used for the transport of iron into the cell. Siderochromes of the ferrichrome type are cyclic peptides containing three hydroxamic acid groups chelated to the metal. Because of the difficulty in carrying out peptide synthesis with substrates containing higher oxidation states of nitrogen, no general synthesis of siderochromes is available. We propose a chemical synthesis of side-chain retroferrichrome, a compound identical to ferrichrome except that the hydroxamic acid groups are inverted. Utilizing standard procedures, a cyclic peptide containing three residues of glycine and three residues of the ethyl ester of L-alpha-aminoadipic acid will be synthesized. Reaction of the ester groups with N-methylhydroxylamine will yield side-chain retroferrichrome. This procedure eliminates the necessity of utilizing derivatives of amino acids containing higher oxidation states of nitrogen. Most important, slight modifications of the procedure will allow the ready synthesis of a series of analogs of ferrichrome in which the amino acids of the cyclic peptide and/or the side chains of the hydroxamate functions may be varied. These compounds will be examined for biological activity as ferric ionophores, as antibiotics, and as potential agents for alleviating the problems of iron overload in humans, e.g., Cooley's anemia. Comparison of the activity of the compounds will also allow a correlation of structure and function with respect to ionophore activity.